How much hay you lose depends on both your storage method and your climate. The same outdoor uncovered storage that loses 25% in the dry Southwest loses 40%+ in the humid Southeast. This reference table combines both variables.
Dry Matter Loss by Storage Method and Climate
| Storage Method | Dry Climate (West, Plains) | Moderate Climate (Midwest, Mid-Atlantic) | Humid Climate (Southeast, PNW) |
|---|---|---|---|
| Barn, off concrete/gravel | 1–3% | 2–5% | 3–6% |
| Barn, bare dirt floor | 3–7% | 5–10% | 7–14% |
| Outside, gravel pad + tarp | 4–8% | 6–12% | 8–16% |
| Outside, gravel pad, no tarp | 6–12% | 10–18% | 14–24% |
| Outside, timber/pallet base, tarped | 8–14% | 12–20% | 15–26% |
| Outside, bare ground, tarped | 12–22% | 20–32% | 24–38% |
| Outside, bare ground, no cover | 18–30% | 25–40% | 32–50% |
Data drawn from University of Kentucky, Wisconsin, Tennessee, and Oregon State Extension research. Ranges reflect variation in bale density, hay type, and specific site conditions.
The Dollar Cost of Storage Decisions
At $100 per bale, 50 bales, over a typical winter storage period:
- Barn on gravel (5% loss): $250 lost to storage
- Gravel pad + tarp, moderate climate (9% loss): $450 lost
- Bare ground, no cover, moderate climate (32% loss): $1,600 lost
- Bare ground, no cover, humid climate (41% loss): $2,050 lost
A $1,000 gravel pad investment in a humid climate recovers its cost in under one storage season compared to bare-ground storage.
Disclaimer: Loss ranges are from published university research and represent typical results. Actual losses vary with specific site conditions, hay type, and bale density.